Psychiatrists have speculated about a potential link between gluten and schizophrenia for more than three decades. In fact, the term "bread madness" was coined half-a-century ago to describe schizophrenia there were reports of mental patients recovering spontaneously when bread products (i.e., the bulk of gluten-containing foods in their diets) weren't available.
Although there have been some case reports of patients with schizophrenia improving with a gluten-free diet, even researchers in the field speculate that only a very small percentage of schizophrenics may ultimately benefit from dietary interventions such as a gluten-free diet. It's also important to recognize that there are no currently accepted dietary recommendations regarding gluten and schizophrenia. Still, researchers are beginning to look at the complex connections that may exist in the immunology of celiac disease, gluten sensitivity, and schizophrenia.
Schizophrenia: Severe Mental Disorder
Schizophrenia is a chronic, severe and potentially disabling brain disorder. It affects about 1% of the overall population. People with schizophrenia suffer from a variety of different symptoms, but may hear voices (hallucinations) or believe people are controlling them or plotting against them (delusions).
To control schizophrenia, physicians generally prescribe antipsychotic medication. Support from a psychiatric team is often an essential component of care.
Although in some people the disease can be controlled enough for them to be productive members of society, others with schizophrenia are significantly disabled. Although most people with schizophrenia aren't violent toward others, approximately 10% ultimately commit suicide.
Wheat Gluten As A Possible Causative Factor In Schizophrenia?
Back in 1976, researchers published a study in Science speculating that the gluten protein in wheat caused or promoted schizophrenia. "Schizophrenics maintained on a cereal grain-free and milk-free diet and receiving optimal treatment with neuropleptics [i.e., antipsychotic drugs] showed an interruption or reversal of their therapeutic progress during a period of 'blind' wheat gluten challenge," the scientists wrote. "After termination of the gluten challenge, the course of improvement was reinstated. The observed effects seemed to be due to a primary schizophrenia-promoting effect of wheat gluten."
As the years passed, more studies chimed in on the potential effects of gluten in schizophrenia, with mixed results. A study published in 1981 kept eight chronic schizophrenia patients on a gluten-free, milk-free diet and then challenged them with wheat gluten for five weeks. The study found no difference in their schizophrenia symptoms when they were consuming gluten.
However, in a 1986 study, researchers studied 24 patients, primarily people with schizophrenia, on a gluten-free diet, and found that two of those people improved during the gluten-free period and relapsed when the gluten-containing diet was reintroduced.
More recent research has noted this effect of the gluten-free diet in a small subset of patients with schizophrenia, and has recommended large-scale epidemiological studies and clinical trials to determine why this happens and which schizophrenia patients might benefit.
Schizophrenia Involves Gluten Antibodies, But Different Ones Than Celiac Disease
People who have untreated celiac disease (i.e., those who are eating a conventional diet with gluten-containing foods) show high levels of specific antibodies, including the tTG-IgA and EMA-IgA antibodies, when celiac blood tests are performed. These tests are specific to the intestinal damage found due to gluten in celiac disease.
Some people with schizophrenia, meanwhile, show high levels of other antibodies to gluten notably the AGA-IgG and the AGA-IgA antibodies. For example, one study that looked at 1,401 schizophrenia patients found 23% of them had moderate to high levels of AGA-IgA.
The AGA-IgA and AGA-IgG antibodies are considered less specific to celiac disease they indicate an immune system reaction to gluten is going on, but not the specific villous atrophy found in celiac disease.
Indeed, a study that looked at people with celiac disease and people with schizophrenia separately found the two groups seemed to be reacting to different parts of the gluten protein, indicating that any immune system response to gluten in schizophrenia is different from that of celiac disease, and is independent of any potential intestinal damage.
Those with schizophrenia whose blood test results showed antibodies to gluten did not necessarily have the celiac disease genes, the researchers concluded, adding, "our results reveal an immunologic response to gluten in individuals with schizophrenia that is clearly different from that in celiac disease."
Non-Celiac Gluten Sensitivity Possibly Implicated in Schizophrenia
Although it's not generally accepted in the mental health field, University of Maryland Center for Celiac Research director Dr. Alessio Fasano says that an as-yet undefined subset of people with certain mental disorders, including schizophrenia and also autism, seem to improve or even recover on a gluten-free diet, even if they don't have celiac disease.
However, there's currently no accepted way to test for gluten sensitivity. There's also no accepted way to determine whether a schizophrenia patient would benefit from the gluten-free diet; the AGA-IgA and AGA-IgG tests don't seem to pick up everyone with the condition. Researchers currently are working to identify a specific biomarker that could lead to a medical test that will identify most or all people with gluten sensitivity, including those with schizophrenia.
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